摘要
采用传统固相反应法合成了双掺杂La_(0.67)Ca_(0.33-x)Sr_xMnO_3(x=0,0.05,0.15)粉体,研究了烧结温度对La_(0.67)Ca_(0.33-x)Sr_xMnO_3(x=0,0.05,0.15)结构、微观形貌和金属-绝缘体相转变温度的影响规律。结果表明:烧结温度的升高对微观形貌及结构影响较小,双掺杂有效改善了材料体系的相转变温度。当烧结温度为1400℃,掺杂量x=0增加至x=0.05时,材料体系为正交相,相转变温度从–20℃升高至6℃。掺杂量继续增加至x=0.15,材料体系从正交相转变为六方相,相转变温度升高至17℃。当掺杂量相同时,相转变温度随烧结温度的升高而升高。具有上述智能相变特性的材料体系可以作为长寿命卫星主动热控技术的重要候选材料。
Double-doped La0.67Ca0.33-xSrxMnO3（x=0, 0.05, 0.15）powders were synthesized by traditional solid-state reaction method. Effects of sintering temperature on structure, micro morphology and metal-insulator phase transition temperature of La0.67Ca0.33-xSrxMnO3 ceramic were systemically studied. The results showed that sintering tem- perature had little influence on crystallinity or micro morphology of as-prepared ceramic, while double-doping effectively changed the phase transition temperature of the ceramics. When the ceramics sintered at 1400℃, the metal-insulator phase transition temperature increased from -20℃ to 6 ℃ and the ceramics stabilized in orthorhom-bic structure as the doping level varing from x=0 to x=0.05. At the doping level x=0.15, the crystal structure changed from rhombohedral to orthorhombic and the metal-insulator transition temperature was 17℃. Under the same doping concentration, the metal-insulator phase transition temperature of the ceramics increased with the in- crease of sintering temperature. The above mentioned material may be an ideal candidate for active thermal control technology of long life satellites.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第9期943-947,共5页
Journal of Inorganic Materials
